Latch for drill-heads of handpieces of dental engines.



R. C. KREBS.

LATCH FOR DRILL HEADS 0F HANDPIECES 0F DENTAL ENGINES.

APPLICATION FILED 06123, 1914.

1,142,443. Patented June 8, 1915,

THE NORRIS PETERS 60.. PHOTO-LITHQ. WASHINGTON. D. c.

RICHARD c. KREBS, or CHICAGO, InLINoIs.

LATCH FOR DRILL-HEADS 0F HANDPIECES OF DENTAL EI\TGI1\TES.

Specification of Letters Patent. Patentgd J 11 8 1915,

Application filedOctober 23,1914. Serial No. 868,178. 1 I

To all whom it may concern:

Be it known that I, RICHARD 0. Mass, a citizen of the United States, anda resident of Chicago, Cook county, State of Illinois, 5 have inventedcertain new and useful Improvements in Latches for Drill-Heads ofHandpieces of Dental Engines, of which-the following is declared to be afull, clear, and exact description.

This invention relates to hand pieces of dental engines, and moreparticularly, to the latch thereof which is used for holding the tool inplace in the chuck of the head.

The present forms of latches are difficult to manipulate and do noteffectively hold the tool in place after they are worn slightly.

The object of this invention is to overcome such difficulties, and toprovide a latch of improved construction, which shall be cheap, simpleand efiective in operation.

To such ends, this invention consists in the several novel features ofconstruction, arrangement and combination of parts hereinafter fully setforth and claimed.

' piece of a dental engine, showing a simpleembodiment of the presentinvention apview of the head thereof, partly broken away to show certainparts of the interior construction; Fig. 3 is an end view, looking inthe direction of the arrow, 3, in Fig. 2; Fig. 4 is a plan of the partseen in Fig. 2, and Fig. 5 is aperspective view of the latch.

Referring to said drawings, 10 designates the handle of a hand piece ofa dental engine, which may be of the usual and. well known form ofconstruction, having a head, 11, at one end, in which is a chuck, 12,arranged to be rotated by suitable, flexible shafting, in accordancewith the usual, well known practice in hand pieces of dental engines.The tool, 13, used in connection with devices of this kind, has a shank,14, which is inserted into the chuck, 12, and has a flattened portion,15, for engagement With a flattened portion, 16, of the chuck',toinsureits rotation therewith, and at the said upper portion of saidshank, is a reduced neck, 17, above which is a head, 18, thus leaving agroove between the head, 18, and shank, 14., as shown in Fig. 2. Thehead, 11, of the I hand piece is formed with a slot, 19, near its Theinvention is clearly illustrated in the plied thereto; Fig. 2 is' anenlarged side upper edge, as seen in Fig. 3, said slot extending inwardfrom one sideof the head,

for the reception of one part of the latch;

The parts thus far described constitute a hand piece of ordinary andwell known. construction and require no further description, so far asthis specification is concerned.

The latch, 20, which constitutes the subect matter of the presentinvention, has 'a flat portion, 21, slidably seated in the groove, 19,of the head, 11,.and a portion, 22, forming a' thumb piece, lying abovethe part, 23,*-

of the head, 12, which overlies the'slot, 19. The fiat, lower portion ofthe latch, 21, has

a lengthwise extending slot, 24, at its rear end, through which'extendsa screw, 25, for limiting the lengthwise movement of the latch, saidscrew passing through the overhanging part, 23, and into the head, 11.The forward end of the latch, 20, is also provided with a slot, 26, forreceiving the neck, 17, of'the tool shank, 14, the head, 18, of thefshank, being arranged to rest upon the forks of the flat portion, 20,adjacent said slot, 26.

The latch is preferably made of sheet metal stamped up into the formshown, and

the upper thumbpiece' part, 22, is connected to the bottom part, 20, bya curved, connectng portion, 27, while its other end is formed with abent down part, as at 28, said parts 27, 28, engaging with the side ofthe head,

11, and preventing transverse movement of the latch. piece portion isformed with a downwardly extending, dented portion, 29, which enters ahole, 30, in the overlying part, 23, of the head, and registering withthe chuck, and

' said dented portion bears upon the head, 18,

of the tool shank, when inserted in the chuck. serves the purpose ofpreventing accidental lengthwise movement of the latch after it has beenmoved into engagement with the tool, and also steadies the tool, becauseof its pressure upon its end.

In use, av suitable tool is forced into the chuck from the lower end,until it engages with the square portion, 16, thereof, the neck at thistime being co-incident with the slot, 19, of the head, 11. Prior tothisztime,

the latch is. withdrawn to the position shown in dotted lines in Fig. 4,and after the tool has been inserted in the chuck, the user places histhumb upon the overhanging por- Preferably, the upper thumb Thisdownwardly dented portion tion, 22, of the latch, and moves it forwarduntil the depressed portion, 29, enters the hole, 30, the forked ends ofthe latch at this time straddling the neck, 17, of the tool shank andunderlying the head, 18, thereof, thus preventing the withdrawal of thetool.

More or less variation of the exact details of construction is possiblewithout departing from the spirit of this invention, and I desire,therefore, not to limit myself to the exact form of construction shownand described, but intend in the following claims to point out all ofthe invention disclosed herein.

I claim as new and desire to secure by Letters Patent:

1. In combination with the hand piece of a dental engine and having atransversely extending slot in its head which is covered by the top ofthe head, and a chuck therebelow for the reception of a tool shankhaving a reduced neck at its upper end, arranged to register with saidslot, of a latch member for said tool shank, having a main memberslidably securedin said slot, andbeing slotted for the reception of theneck of the shank, and a thumb piece lying outside of the head andconnected to said main member, said latch member being held on said headagainst lateral movement with respect thereto.

2. In combination with the hand piece of a dental engine and having atransversely extending slot in its head which is covered by the top ofthe head, and a chuck therebelow for the reception of a tool shankhaving a reduced neck at its upper end, arranged to register with saidslot, of a latch member for said tool shank, having a main memberslidablv secured in said slot, and being slotted for the reception ofthe neck of the shank, and a thumb piece lying outside of the head andconnected to said main member, said latch member being held on said headagainst lateral movement with respect thereto, said thumb piece having adownwardly depressed portion engaging the end of said shank.

3. in combination with the hand piece of a dental engine and having atransversely extending slot in its head, and a chuck therebelow for thereception of a tool shank hav ing a reduced neck at its upper end,arranged to register with said slot, of a latch member for said toolshank, having a fiat member slidably mounted in said slot, said flatmember having a slotted end arranged to receive the reduced neck of thetool shank, and also a slot at its other end, a screw secured in saidhead and extending through said second named slot, said flat portionhaving also a thumb piece portion bent up from one edge thereof, andoverlying said head, the free edge of said thumb piece portion having adownwardly bent tongue for engaging the side of the head.

4:. A. latch for hand pieces of dental engines, comprising a flatportion, formed with two lengthwise extending openings, one edge of saidportion having a narrow part bent up and terminating in a thumb piecelying approximately parallel with said fiat portion, said thumb piecehaving a downwardly bent tongue opposite said narrow edge portion.

5. A latch for hand pieces of dental engines, comprising a Hat portion,formed with two lengthwise extending openings, one edge of said portionhaving a narrov part bent up and terminating in a thumb piece lyingapproximately parallel with said flat portion, said thumb piece having adownwardly bent tongue opposite said narrow edge portion, and havingalso a central, downwardly extending dented portion.

RICHARD C. KREBS.

"Witnesses CHARLES O. SHERVEY, ANNA J. GOHON.

Copies of this patent may be obtained for five cents each, by addressingthe Commissioner of Patents,

Washington, D. B.

